The invention relates to a method for calculating and correcting the disaggregation time of a spin-stabilized programmable projectile, wherein a correction factor, which has been multiplied by a velocity difference, is added to the disaggregation time, and wherein the velocity difference is formed from an actually measured projectile velocity and from a lead velocity of the projectile. The invention further relates to a device for executing the method.
Such projectiles, which have become known from a publication OC 2052 d 94 of the Oerlikon Contraves company of Zxc3xcrich, Switzerland, have sub-projectiles, which can destroy an attacking target by multiple impacts if, following the ejection of the sub-projectiles at the disaggregation time, the expected area of the target is constituted by a cloud formed by the sub-projectiles. However, in this case it is not always possible to achieve a satisfactory impact, or respectively shoot-down probability, because of variations in a predetermined optimal disaggregation distance which, for example, are caused by variations in the projectile velocity.
A method for calculating the disaggregation time of a programmable projectile of the above described type, by means of which the impact, or respectively shoot-down probability, can be improved, has become known in U.S. Pat. Nos. 5,814,755; 5,814,756 and 5,834,675. In this case, the calculation is at a minimum based on an impact distance to a target object, a projectile velocity measured at the muzzle of a gun barrel, and a predetermined optimal disaggregation distance between an impact point of the target and a disaggregation point of the projectile. The optimal disaggregation distance provided is kept constant by means of correcting the disaggregation time of the projectile. Correction is performed in that a correcting factor, which is multiplied by a velocity difference, is added to the disaggregation time. The projectile velocity difference is formed from the difference between the actually measured projectile velocity and a lead velocity of the projectile, wherein the lead velocity is calculated from the average value of a number of previous successive projectile velocities. The corrected disaggregation time is transmitted inductively to the projectile at the time of firing in order to set a time fuse of the projectile.
With this method, the actual projectile velocity is determined by means of a measuring device arranged at the muzzle of the gun tube. The measuring device consists of two annular coils arranged at a defined distance from each other. In the course of the passage of the projectile through the two annular coils, a pulse is generated in each annular coil in a rapid sequence because of the change in the magnetic flux caused by this passage. The pulses are provided to an electronic evaluation device, in which the projectile velocity is calculated from the chronological distance between the pulses and the distance between the annular coils.
In connection with guns which, because of their design. (Gatling guns, guns firing large projectiles), do not permit the present arrangement, it is advantageous to process and transmit the information transmission and the measurement results at point different from the muzzle.
The determination of the projectile velocity and the correction of the disaggregation time is performed in the projectile after it has been fired. The velocity measurement takes place in the form of a measurement of an initial time needed for a defined number of revolutions of the projectile, wherein the velocity difference, which must be multiplied by a correction factor, is expressed by a time difference formed by the initial time and a predetermined second time.
The advantages obtained by means of the invention lie in particular in that errors, which can occur when utilizing measurement devices arranged at the muzzles of the guns, are eliminated, and that the projectiles can also be used for guns which do not have such measuring devices.
The invention will be explained in greater detail in what follows by means of several exemplary embodiments and in connection with the drawings.